Circularly polarizing plate and display device

Patent metadata

Field	Value
Publication number	US-2017192145-A1
Application number	US-201715465914-A
Country	US
Kind code	A1
Filing date	Mar 22, 2017
Priority date	Sep 30, 2014
Publication date	Jul 6, 2017
Grant date	—

Abstract

The present invention provides a circularly polarizing plate that improves the visibility of black color in an oblique direction when being applied to a display device and having a small thickness, the display device including a circularly polarizing plate. The circularly polarizing plate is a circularly polarizing plate including, in this order, a polarizer, a λ/2 plate, and a λ/4 plate, in which the λ/2 plate is a laminate of a first A-plate and a first C-plate, the λ/4 plate is a laminate of a second A-plate and a second C-plate, one of the first C-plate and the second C-plate is a cellulose acylate film having a predetermined Rth, and the other of the first C-plate and the second C-plate is an optically anisotropic layer including a liquid crystal compound having a predetermined Rth or a cellulose acylate film having a predetermined Rth.

First claim

What is claimed is:

1 . A circularly polarizing plate comprising, in this order:
a polarizer, a λ/2 plate; and a λ/4 plate, wherein the λ/2 plate is a laminate of a first A-plate and a first C-plate, the λ/4 plate is a laminate of a second A-plate and a second C-plate, one of the first C-plate and the second C-plate is a cellulose acylate film having a retardation Rth in a thickness direction at a wavelength of 550 nm of 30 to 50 nm, the other of the first C-plate and the second C-plate is an optically anisotropic layer including a liquid crystal compound having a retardation Rth in a thickness direction at a wavelength of 550 nm of −60 to −30 nm, in a case in which the first A-plate is a negative A-plate, Expressions (1) and (2) below are satisfied, and in a case in which the first A-plate is a positive A-plate, Expressions (3) and (4) below are satisfied.
0< Nz factor of the λ/2 plate≦0.35  Expression (1)

0.65≦ Nz factor of the λ/4 plate<1  Expression (2)

0.65< Nz factor of the λ/2 plate<1.0  Expression (3)

0< Nz factor of λ/4 plate≦0.35  Expression (4)

2 . The circularly polarizing plate according to claim 1 ,
wherein the first A-plate and the second A-plate each include a liquid crystal compound.

3 . The circularly polarizing plate according to claim 1 ,
wherein the liquid crystal compound in the optically anisotropic layer is a rod-like liquid crystal compound.

4 . The circularly polarizing plate according to claim 2 ,
wherein the liquid crystal compound in the optically anisotropic layer is a rod-like liquid crystal compound.

5 . The circularly polarizing plate according to claim 1 ,
wherein the circularly polarizing plate has a thickness of 60 μm or less.

6 . The circularly polarizing plate according to claim 2 ,
wherein the circularly polarizing plate has a thickness of 60 μm or less.

7 . The circularly polarizing plate according to claim 3 ,
wherein the circularly polarizing plate has a thickness of 60 μm or less.

8 . The circularly polarizing plate according to claim 4 ,
wherein the circularly polarizing plate has a thickness of 60 μm or less.

9 . A display device comprising:
the circularly polarizing plate according to claim 1 .

10 . A display device comprising:
the circularly polarizing plate according to claim 2 .

11 . A display device comprising:
the circularly polarizing plate according to claim 3 .

12 . A display device comprising:
the circularly polarizing plate according to claim 4 .

13 . A display device comprising:
the circularly polarizing plate according to claim 5 .

14 . A display device comprising:
the circularly polarizing plate according to claim 6 .

15 . A display device comprising:
the circularly polarizing plate according to claim 7 .

16 . A display device comprising:
the circularly polarizing plate according to claim 8 .

Assignees

• Fujifilm Corp

Inventors

• Furuki Yusuke
• Yamada Naoyoshi
• MUTO Masakane

Classifications

• G02B5/3041

  comprising multiple thin layers, e.g. multilayer stacks · CPC title

• H01L51/5293

  Electricity · mapped topic

• G02B5/3016 Primary

  involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528) · CPC title

• H10K59/8793

  Arrangements for polarized light emission (H10K59/8791 takes precedence) · CPC title

• H10K59/8791

  Arrangements for improving contrast, e.g. preventing reflection of ambient light · CPC title